Amphinome

Body elongate, rectilinear, with indeterminant number of chaetigers. Prostomium reduced, with anterior and posterior lobes present. Five cephalic appendages present on prostomium: paired antennae and palps on anterior lobe; median antenna on posterior lobe. Caruncle small, heart-shaped, with free lateral wings, marginally notched to accommodate median antenna; suspended above body wall by stalk, latter attached and confined to chaetiger 1. Chaetiger 1 complete dorsally and incomplete ventrally. Parapodia biramous; notopodia and neuropodia raised above body wall, encompassed by conspicuous collars. Notochaetae include capillaries lacking spurs or prongs and harpoons with two rows of barbs. Neurochaetae spinous, resilient, tapering distally to curved unidentate hooks in adults (bidentate in juveniles); internally solid, non-retractile. Noto- and neuroaciculae hastate. Branchiae dichotomously branching tufts from chaetiger 3 and continuing almost to end of body. Dorsal cirri cirriform. Ventral cirri subulate, distally pointed. Dorsal anus opening on terminal two-three chaetigers. Pygidial cirrus unpaired.